Hydraulic draft rigging



A. L. ZANOW HYDRAULIC DRAFT RIGGING March 16, 1965 2 Sheets-Sheet 1 Filed May 17, 1963 INVENTon ift/Pfff l.. ,2W/WW d@ W ,HTM/VIV March 16, 1965 A. l.. zANQw HYDRAULIC DRAFT RIGGING- 2 Sheets-Sheet 2 Filed May 1'7. 1963 ,l rinvii/11111111111,

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United States Patent Oiice 3,173,552 Patented Mar. 16, 1965 3,173,552 HYDRAULIC DRAFT RIGGING Andrey L. Zanow, Cleveland, Ohio, assignor to National Castings Company Filed May 17, 1963, Ser. No. 281,271 12 Claims. (Cl. 213-43) This invention relates to an improved draft and buit mechanism for railway vehicles. The mechanism herein disclosed permits the best features of a hydraulic cushioning unit and a resilient cushioning unit to be combined in a single draft and buff mechanism.

Recent developments in the railway field have led to the conclusion that the conventional friction type draft gear and the conventional rubber type draft gear hitherto widely employed do not provide the most effective cushioning under the wide range of conditions encountered by the typical railway vehicle. Hydraulic cushioning of railway vehicles is a relatively recent development in the field that provides selected desirable features. The invention herein disclosed permits the best features of the widely-used rubber and spring type gears to be combined with the newer hydraulic gear and incorporated into a single draft gear mechanism.

It is, therefore, the primary object of this invention to provide a draft gear mechanism combining the best features of hydraulic and resilient cushioning units into a single dnaf-t gear mechanism.

It is another object of this invention is to provide a draft gear mechanism having cushioning elements that function in series when subjected to buff forces and in parallel when subjected to draft forces.

A further object is to provide draft rigging capable of extended hydraulically cushioned travel in a direction for absorbing buff forces but substantially shorter and more softly cushioned travel in the direction for absorbing draft forces.

Another object is to effect the foregoing object through the use of hydraulic snubbing in cushioning draf-t forces.

In brief, the invention resides in a draft rigging wherein a draft gear comprises two resilient cushioning elements and a hydraulic snubbing device interrelated with a coupler and the sill structure of a railway vehicle to (l) place the hydraulic device in series additive force relation with one of the resilient elements and in parallel additive force relation with the other element during application of buff forces to the coupler; and (2) when draft forces are applied to the coupler, tending to pull portions of the rigging forwardly out of a neutral position, to place the one resilient element in parallel additive force relation, and the other resilient element in parallel subtractive force relation with the hydraulic device.

As a brief structural recital, the draft rigging comprises a housing preferably elongate in its front to rear longitudinal direction arranged in longitudinally coextensive relation with sill structure of a vehicle, such as its center sill. The rigging also has a front cushioning unit and a rear cushioning unit received by the housing. The housing has a longitudinally intermediate partition which separates the cushioning units. Preferably, the rear unit consists of a hydraulic device having a cylinder fixed to the housing, a piston reciprocable therein, and a piston rod connecting the piston to an anchor fixed to the sill rearwardly of the housing. The rear unit further comprises a resilient cushioning element standing, e.g., between the rear end of the cylinder and a forward facing surface of the anchor.

Two-member thrust means, such as a coupler and a follower disposed between the front cushioning unit and the rear shank end of the coupler, extends inwardly of the front end of the housing to transmit butlng forces into the front unit and thence into the rear unit, the anchor, and the center sill.

Both the sill and `the housing have reaiwardly-facing stops preferably located in respective front portions thereof. The rigging further comprises rst detent means, such as a key, adapted to engage the rear facing stops above the sill and the housing, and extending transversely of the rigging in abutting relation, at neutral condition of the rigging, with the rear-facing sill stop and a forwardfacing surface of the rear member of the thrust means, i.e., the follower. Consequently, the spring or resilient element of the rear unit urges the housing forwardly until the key engages the sill stops. If the spring has sufcient strength, the front resilient element is compressed slightly at neutral position -to dispose the housing slightly forwardly with respect to a position assumed if the resilient element is not compressed, thereby disposing its rearward-facing stops out of contact with the key but with the key seated against the rear-facing sill stops.

In the preferred construction requiring a front resilient unit of greater resistance to compression than the rear resilient element, the thrust means is consequently normally positioned forwardly relative to the partition in the housing against the above-mentioned housing stops by engagement therewith, e.g., second detent means carried by the coupler, such as protruding portions of a pin which connects the coupler shank in slip connection with the housing. Hence, the position of the housing relative to the sill is established in the first instance by the position of the key relative to the housing under compulsion of the front cushioning unit, then secondarily, in the positioning of the housing relative to the fixed sill by positioning the key against the sill stops under the weaker force exerted on the housing by the rear cushioning element. This arrangement is slack-free and typical of the neutral condition of the rigging.

In the drawing in respect to which the invention is described below:

FIG. 1 is a plan view in section of the draft mechanism in a neutral condition;

FIG. 2 is a vertical section taken along line II-II of FIG. 1;

FIG. 3 is an enlarged view of the midportion of the mechanism generally included between lines III-III and lili-H11 in FIG. 2;

FIG. 4 is a fragmentary vertical longitudinal section of the draft mechanism when subjected to draft forces;

FIG. 5 is a fragmentary vertical section of the draft mechanism when subjected to buff forces;

FIG. 6 is a fragmentary perspective view of the draft mechanism mounted in the center sill of a railway vehicle; and

FIG. 7 is a fragmentary enlarged elevation of a cylinder head and valve structure shown in less detail in the previous figures.

Referring to FIG. l, the rigging 2 has a rear cushioning unit 4 comprising a hydraulic device 5 and resilient means, i.e., the springs 6, and a front resilient unit 7. The mechanism is slidably disposed within the center sill 8 of a railway vehicle. The hydraulic device S is enclosed in a housing 1t) which projects forwardly to also enclose the front cushioning unit 7. A car coupler 12 is operatively connected to the forward end of the housing by means of a connecting pin 14 having upper and lower end por- Itions which function with pin stops 15 at :the forward ends of upper and lower slots 16 as detent means. The connecting pin is movable within the slots 16 in the housing. The housing 10 comprises a forward bell-shaped portion, i.e., that portion which extends and ares forwardly from the pin stop 15 to form a lower carrier iron receptacle 10a and an upper transverse shoulder member 10b. This member is spaced from the frontend of the sill 8 at the neutral position ofthe rigging. At full length of Vtravel of the housing relative to the sill. this member may be used as a stop in conjunction with the front surface of the sill. permits vertical and lateral angling freedom of the'coupler shank relative to the housing.

, The slots16 provides a range of'rnovement of the pinV 14 equal substantially to the longitudinal compression of the cushion 7. Theseslots terminatefrontwardly in xed stops 15xed to the casing; rearwardly they'terminate in stops 15a.

, Disposed between the butt end of the coupler shank 17 and the front unit 7 is a follower 18 providing a seat 18a Vfor the coupler butt end surface. The follower 18 has ,a transverse opening 19 in which is received a key 20which normally functions as a detent means reacting through the The bell-shape ofthe frontportion of the housing-r kdevice do not open at low force levels. draulic device'remains immobilized and rearward movet 4* y f cylinder at lowfor'ce levels. Liquid doesnot pass from the cylinder because the valves internally of the hydraulic Thus, the hyment of the housing 10v is prevented.'n v Y As 4the butling force increases, the rearwardly disposed Vhydraulic device 5 comes into operation to cushion the coupler; The housing 1l) is unable to move rearwardly follower 18 between the cushion 7 and rearwardly facingV l stops 21 xed in the center sill S'as'forward extremities of slots 27 therein through which the key 20 passes. It is to be noted that the key 26 also'extends outwardly of the housing 10 through slots 22a and 22h in the side walls of the housing. vThese slots are of suicient length to permit movement of the key relative to the housing throughout the compression range of the front cushioning unit 7. The couplerY shank 17 and the followerl 18 function as a thrust means acting on the cushion 7 in buif operation although the shank and the follower are adapted to separate when the draft rigging is subjected to draft force of sucient magnitude to compress the cushion beyond its state of compressionV at neutral condition of .there draft rigging.'

providing long ycushioning travel, e.g., 24 inches or more, the` slot 27 allows a full Vrange of inward and outward movement of the housing relative to the sill 8. The slots 2,7 terminate rearwardly in abutments 23 which may be used as emergency stops. However, primary facilities for stopping the housing 10 in moving rearwardly of the sill 8 comprise side abutments 32 as lateral extremities of the housing, and front facing sill or striker abutments 33 iny longitudinal alignment with the side abutments.

Travels of the magnitude desired are achieved `essentially in the length of the hydraulic device 5. Of suitable length is a piston member or rod 24 of the hydraulic device 5 attached -to the rcenter sill by means of an anchor or key 2,6. Slack between key 26, rod 24, and the sill 8V is preferably a minimum. Fixed to the forward extremity of the rod 24 is a piston 25. Thus, there are two points of attachment of the cushioning assembly carried by the: housing 10 to the center sill, the iirst by means of a key- 20 near the butt end of thecoupler, and the second at the force level is determined by means, such asla relief valve 39, which may be of customary design and located within the hydraulic unit. Y Y

Referring to FIG; 3, the hydraulic device 5 vhas an Vinner cylinder 40 Vwith a metering tube 42 fixed concentrically therein. The piston Yand the piston rod 4 have a common axial bore in'coaxial relation with the metering tube whereby the tube is accommodated within the bore, in accordance with movements of the housing 10 relative to the piston and piston rod. Duringcompression of the unit resulting from a buff force beingapplied to the coupler,'t he outer housing 10 with the metering tube 42 moves rearwardly` relative to the xed piston 24V to force uid e from the inner cylinder into the reservoir ,43 formed bei located'at the forwardend of the metering tube, precludes fluid from passing into the outer container until a predetermined force level has been'attained. Hence, if the valve isset for a pressure, e.g., of 5,000 pounds per square inch (p.s.i.),rthe hydraulic unit'will not function until a pressure of 5,000 `tp.s.i. is applied to the valve. The valve 39 thereby requires, the front resilient unit 7 to provide cushioning for all bu' forces that will produce ya pressure Vof less than V5,000 p.s.i. on rthe relief valve. The valve 39 is` desired to avoid utilization Vof the hydraulic device at rear of the mechanism where the piston rod 24 is secured. f

to the center sill by means of the key 26. `Additional vertical support for ,the housing 10 is obtained by an inverted saddle 31 attached to the sill adjacent toits ,front end. The saddle 31vpassesitransversely under a guide member 34 ofthe housing Vattached to and extending A the coupler is subjected to buff forces, the coupler and pin Y 14 move rearwardly against the follower 18 whichV bycompressing the frontl cushioning unit 7 moves relative to the housing 1t). The buing force is then transmitted through the wall 28 into the hydraulic unit 4 and the;v

springs 6 which share in parallel relationship of the'buifY load transmitted thereto through thehousing. An importfy ant Yfeature is that during the initialstages of any buff, blow, when the force levels are'relatively low, only the resilient unit 7 offers any cushioning to the coupler. Rela tive movement of `the cylinder and the piston is prevented throughV prevention of passage of any liquid from the the lowerrbuing force levels; The rate lof compression of rthe hydraulic device after its actuation is determined by the configuration of the orifice made by bore of the piston 25 and the outer surface of the Vtube 42 during closure. In buff, thehydraulic device valso vprevents the springs of the rear unitffrom coming into play since compression thereof Vis dependent on movement of the housing 10.

Thus, in butt, the forward resilient unit 7 is the first to come into koperation because of the purposely restricted functioning of thehydra'ulic device. Then the hydraulic device and the springs 6 come into operation. Hence, the two unitsfunctionin series to provide cushioning at different force levels. Normally, the buff forces `on a couple far exceed the draft forces. By providing cushioning from a resilient unit at the lower force levels, and providing a hydraulicfdevice for the higher force levels, the combinedfeatures of both units are available in a single draft gear mechanism. It isy to be vnoted in buff, that while 'the forces resisting coupler movement by the rhydraulic device 5 and the springs 6 are parallel, these forces considered together are in series relation withthat which is derived from the front unit 7.

ln draft, the mechanism provides cushioning to the coupler by actua/ting "the cushioning vunits in parallel. However, it is to be noted thatthe springs 6 Iof the rear unit are now acting oppositely with yrespect .to` the front unit 7 and the hydraulic devices. [While force contributed by the springs 6 is parallel to that contributed .by the unit 7` andtheV device 5, such force must be subtracted yfrom the-sum contributed by the front unit 7 and the deviceV 5. The coupler being operatively connected to the The resilient unit 7, under draft, will be compressed between wall 28 and key 20. The key 2?, which passes through slot 27 in center sill 8, is lodged in the forward end of the slots 27 against the sill stops 2l. As the forward unit 7 is compressed between the key 20 and the Wall 28, the coupler 12 separates from the follower 1S to develop a gap 38. At the same time, the hydraulic device is extended through some of .the cushioned travel as hereinafter described remaining to the piston 2S within the cylinder 40; simultaneously the springs 6 are expanding and neutralize some of the cushioning force derived from the device and the front unit 7. A comparison of FIG. 4 with FIGS. l and 2 which illustrate the rigging at neutral condition, shows in FIG. 4 that the draft rigging has undergone substantially all of the short stroke movement available to the housing l() in moving forwardly relative to the piston 25 and the sill 10 under conditions of draft.

In draft, the hydraulic device 5 functions differently from that in buff. Referring to FIG. 3, which is an enlarged view of that portion of FIG. 2 in brackets, there is shown that portion of the device 5 that provides cushioning when subjected to draft forces. The housing l0, in draft, is pulled forwardly by the coupler in contrast to being driven rearwardly when subjected to buff forces. The piston 25 is anchored to the center sill structure by means of key 26 and the piston rod 24 and thereby held stationary. When draft forces are applied to the mechanism, the portion of the fluid in the cylinder 40 marked A is forced outwardly in metered fashion, as indicated by the arrows indicating fluid flow, through an orifice 44 in cylinder 4) into the reservoir 43. It should be noted that at the same instant that the hydraulic unit operates as a result of draft forces being applied to the coupler, the resilient unit 7 is also being compressed. Thus, both the hydraulic and cushioning units are functioning simultaneously in draft. Under the buff conditions, ball check valve 46 opens to permit fluid to flow from the reservoir into the cylinder to the rear of the piston 25. In draft, or in returning the draft gear to neutral condition from a buffed condition, the metering tube 42 is not used to control the rate of piston movement as it is in buff. In returning to neutral condition from a buffed condition, the housing 10 moves forwardly and liquid flows relatively freely from the reservoir 43 into the cylinder forwardly of the piston through openings subject to restriction under bu'ing action by a ring-type check valve 47.

The hydraulic unit is maintained in an extended position by means of the springs 6. These springs keep the housing 10 forwardly in its neutral position in equilibrium with an opposing force provided by the front unit 7. The forward end of the spring is in abutting engagement with wall 5@ of the housing, and the rearward end of the spring is in abutting engagement with wall 52 on the rearward portion of the piston member. The spring is extended slightly because of forward movement of the housing from neutral position when the mechanism is subjected to draft forces. It is when the mechanism is subjected to buff loads that actuate the hydraulic unit rthat the spring is greatly compressed. The spring not only serves to restore the hydraulic unit to its extended position, but provides resistance to compression resulting from draft and buff forces being applied to the mechanism.

One of the distinctive features of the mechanism herein described is that the housing lil encloses the ltwo cushioning units and is attached to the automatic coupler. Another feature is that the housing, which functions in a manner similar to a yoke, is an integral part of one cushioning unit and provides a housing for the unit.

What has been disclosed herein is a unique draft gear mechanism that combines the best features of hydraulic and resilient draft units into a single draft gear mechanism. The mechanism not only provides improved cushioning for the associated vehicle, but provides great flexibility in the selection of suitable units. The cushioning provided by the hydraulic unit may be readily adjusted to meet unusual service conditions, and the forwardly disposed resilient unit may be easily replaced.

The terms and expressions which have been employed are used as terms of description and not of limitation and there is no intention of excluding such equivalents of the invention described, or of the portions thereof, as fall within the scope of the claims.

What is claimed is:

l. Draft rigging for a railway vehicle comprising:

(A) a housing having a front-to-rear longitudinal direction and a fixed longitudinally intermediate partition;

(B) a sill in external longitudinally coextensive relation with the housing;

(C) a front cushioning unit and a rear cushioning unit, both resistant to contraction, received by said housing at frontward and rearward sides, respectively, of the partition;

(D) thrust means disposed frontwardly of the housing, comprising front and rear longitudinally separable members, and movable rearwardly against the front unit;

(E) anchor means connected to said sill rearwardly of the housing withl respect to which the housing is movable rearwardly to compress the rear unit;

(F) rearward-facing stop means on said sill;

(G) detent means engageable in abutting relation with a forward-facing surface of said rear member and engaging said surface and said stop means in the neutral condition of the rigging;

(H) second detent means carried by said front member; and

(I) rearward-facing stop means mounted on the housing in frontward engageable relation with the second detent means;

(I) said front cushioning unit hav-ing greater resistance to compression than said rear cushion, at said neutral condition, to maintain the second detent means against said stopping means on the housing.

2. The draft rigging of claim 1 comprising:

energy-absorbing means reacting between the housing and the sill in movements of the housing relative to the sill forwardly from its position in said neutral condition.

3. The draft rigging of claim l wherein:

the rear cushioning unit comprises a double-acting hydraulic device for snubbing movements of the housing relative to the sill in both directions from its position at said neutral condition.

4. The draft rigging of claim l wherein the rear cushioning unit comprises: v

(l) a hydraulic device having a cylinder xed to said housing, a piston, and a piston rod fixed to said rear thrust means; and

(2) a compression spring reacting between the housing and the anchor means in parallel force relation with said device.

5. The draft rigging of claim l wherein the rear cushioning unit comprises:

(l) a double-acting hydraulic device having a cylinder fixed to said housing, a piston disposed internally intermediately of the ends of the cylinder at said neutral condition affording hydraulically snubbed movement of the housing in either longitudinal direction relative to the sill, a piston rod fixed to said anchor means, and a compression spring surrounding said piston rod and reacting with opposed surfaces of the cylinder and the anchor means to urge said device to an extended condition;

said spring being in parallel additive force relation with said device and the spring and the device in combination, and being in series additive force relation with the front cushioning 7 unit during rearward movements` of the entire frontthrust means relative to `the sill; and

I said spring being in parallel subtractive .force relationwith said devicerandV the front cushioning unitduringmovements of said front member and the housing forwardly of saidrneutral con-V dition. Y V y 6. The draft rigging of claim 1, wherein the rear Vcushioning unit comprises: j

` (l) a hydraulic device having a cylinder Xed to said housing, a piston, anda piston rod fixed to the rear Y thrust means; and i Y y(2) a compression spring reacting between the housing Y and the anchor means in parallel-force relation with said device; Y l

said hydraulic device having pressure sensitive valve means disposed foropening upon a predetermined pressure within said cylinder develyoped in movements of the housing in a rearward direction. i

7. A draft rigging for a railway vehicle comprising:

(A) a housing having a front-to-rear longitudinal d"- rection, a lixed longitudinally intermediate partition, and a rearward-facing Stop;

(B) a sill fixed in said vehicle in external longitudinally coext'ensiveV relation with the housing, the sill having a rearward-facing stop;

(C) anchor means connected to the sill rearwardly of kthe housing; v

(D) a rear cushioning unit comprising;

(l) Aa hydraulic device having a cylinder fixed inv the housing at the rear of the partition, apiston slidably received in the cylinder, and a piston rod connecting the 'piston with the anchor means; and

(2) a spring concentric to the piston rod bearing on the'rear end of the cylinder and a forwardfacing surface of the anchor means;

(E) a frontY cushioning unit located forwardly of theA partition; p v- (F) a car coupler having a head and a shank extending rearwardly therefrom into said housing;

(G) means lfor connecting the coupler shank to the housing normally engaging said housing stop to limit forward movement of the4 coupler relativeV to the housing, said connecting means allowing rearward movement of the coupler upon longitudinal compression of said front unit; Y

Y (H) a follower Ydisposedbetween said front unit and the rear end of the shank `in separable relation with the latter; andV (l) a key extending transversely of said` longitudinal p direction in normally abutting relation' with a forward-facing surface of thek follower and saidv sill stop; and Y Y said front unitbeing suhstantiallymore vresistant Y tofV compression .than said springto maintain said connecting means, saidV follower, said coulplcr shank, and said housing stop in substantially slack-free relationship at the neutral and draft Yconditions ofthe rigging. 8. The draftrigging of claim 7 wherein:

Vsaid devicehasl a liquid reservoir in communication with said cylinder, and said housing has an external wall surrounding lsaid cylinder inspaced relation therewith ,to provide said reservoir..

9. The draft rigging of claim 8 wherein:

f said device comprises pressure-relief valve means maintaining said devicev and said spring inoperative as shock absorbingmedia during applicationof rearward buii'forces on the front vunit while the pressure within ksaid cylinder remainsk below said predeterymined pressure; and v liquid metering means in communication with the 1 pressure relief means forl restrictingthe discharge of p liquid passing therethrough from the cylinder. V l0. The draft rigging of claim 7jwherein:

the housing comprises a front bell-shaped portion flaring forwardly from `said housing stop, said front portion terminating forwardlyk and downwardly in a carrier iron receptacle.

` ll. The draft rigging of claim lO'wherein:

said housing terminates forwardly and laterally as side abutments inr longitudinal, usually-spaced alignment with respect to lateral striker abutments of said sill, said side abutmentsadapted to cooperate with said striker abutments in stopping rearward movement of the housing relative to the sill.

' 12. The draft rigging of *claimv lOkwherein:

n said housing comprises la guidemember extending horizontally rearwardly from said receptacle; and

lthe rigging comprises an inverted saddle attached to f a frontend portion of the ,sill and extending under `said guide' memben `No Hreferences cited. 

1. DRAFT RIGGING FOR A RAILWAY VEHICLE COMPRISING: (A) A HOUSING HAVING A FRONT-TO-REAR LONGITUDINAL DIRECTION AND A FIXED LONGITUDINALLY INTERMEDIATE PARTITION; (B) A SILL IN EXTERNAL LONGITUDINALLY COEXTENSIVE RELATION WITH THE HOUSING; (C) A FRONT CUSHIONING UNIT AND A REAR CUSHIONING UNIT BOTH RESISTANT TO CONTRACTION RECEIVED BY SAID HOUSING AT FRONTWARD AND REARWARD SIDES, RESPECTIVELY, OF THE PARTITION; (D) THRUST MEANS DISPOSED FRONTWARDLY OF THE HOUSING, COMPRISING FRONT AND REAR LONGITUDINALLY SEPARABLE MEMBERS, AND MOVABLE REARWARDLY AGAINST THE FRONT UNIT; (E) ANCHOR MEANS CONNECTED TO SAID SILL REARWARDLY OF THE HOUSING WITH RESPECT TO WHICH THE HOUSISNG IS MOVABLE REARWARDLY TO COMPRESS THE REAR UNIT; (F) REARWARD-FACING STOP MEANS ON SAID SILL; (G) DETENT MEANS ENGAGEABLE IN ABUTTING RELATION WITH A FORWARD-FACING SURFACE OF SAID REAR MEMBER AND ENGAGING SAID SURFACE AND SAID STOP MEANS IN THE NEUTRAL CONDITION OF THE RIGGING; (H) SECOND DETENT MEANS CARRIED BY SAID FRONT MEMBER; AND (I) REARWARD-FACING STOP MEANS MOUNTED ON THE HOUSING IN FRONTWARD ENGAGEABLE RELATION WITH THE SECOND DETENT MEANS; (J) SAID FRONT CUSHIONING UNIT HAVING GREATER RESISTANCE TO COMPRESSION THAN SAID REAR CUSHION, AT SAID NEUTRAL CONDITION, TO MAINTAIN THE SECOND DETENT MEANS AGAINST SAID STOPPING MEANS ON THE HOUSING. 